/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alipay.sofa.jraft.rhea.util.internal;

import java.lang.reflect.Field;

import sun.misc.Unsafe;

/**
 *
 * @author jiachun.fjc
 */
public class UnsafeIntegerFieldUpdater<U> {
    private final long   offset;
    private final Unsafe unsafe;

    UnsafeIntegerFieldUpdater(Unsafe unsafe, Class<? super U> tClass, String fieldName) throws NoSuchFieldException {
        Field field = tClass.getDeclaredField(fieldName);
        if (unsafe == null) {
            throw new NullPointerException("unsafe");
        }
        this.unsafe = unsafe;
        offset = unsafe.objectFieldOffset(field);
    }

    public void set(final U obj, final int newValue) {
        unsafe.putInt(obj, offset, newValue);
    }

    public int get(final U obj) {
        return unsafe.getInt(obj, offset);
    }
}
